Obstacles to carrying out the death penalty are mounting, keeping the number of executions conducted in the United States low, experts say. Only a few of the 31 states where capital punishment remains legal still put prisoners to death. And the decision in May by one of the world’s top pharmaceutical companies to prohibit its drugs from being used in executions placed another hurdle in the way of states that allow capital punishment. To use lethal injections, states must now obtain substitute drugs from compounding pharmacies that want their identities kept secret. The constitutionality of Florida’s death penalty sentencing procedures also is being challenged, presenting yet another obstacle to capital punishment. Alongside all of these legal and logistical conflicts, the fundamental question of the morality of the death penalty remains hotly contested.

In this handout photo provided by the Charleston County Sheriff's Office Detention Center, Dylann Roof is seen in his booking photo after being arrested for the June 2015 mass shooting in Charleston, S.C., that killed nine people. Federal prosecutors are seeking the death penalty for Roof. (Getty Images/Charleston County Sherrif’s Office)

A leading pharmaceutical company has vowed to block the use of its drugs to put condemned prisoners to death by lethal injection — the predominant execution method in the United States. Pfizer, a New York-based global drug-making giant, announced in mid-May that it would limit sales of seven drugs used in lethal injections to a “select group of wholesalers, distributors and direct purchasers” who promise not to resell the products for use in executions.

“Pfizer makes its products to enhance and save the lives of the patients we serve,” the company said. 1